Textile treating



United States Patent 3,101,236 TEXTHLE TREATING Victor S. Salvin,Charlotte, N.C., Basil S. Sprague, Berkeley Heights, N.J., and FredFortess, Charlotte, N.C., v assignors to Celanese Corporation ofAmerica, New

York, N.Y., a corporation of Delaware No Drawing. Original applicationDec. 2, 1954, Ser. No. 472,758, now Patent No. 2,982,597, dated May 2,1961. Divided and this application July 18, 1960, Ser. No. 43,285 I 3 14Claims. (Cl. 8-59) This application is a division of our copendingapplication Serial Number 472,758, filed December 2, 1954, now U.S.Patent No. 2,982,597, and acontinuatio-n-inpart of our applicationSerial Number 406,350, filed January 26, 1954, now abandoned.

This invention relates to the dyeing of cellulose acetate of very highacetyl value and relates more particularly to the production ofwash-fast dyed textile materials.

As is well known, the cellulose acetate textile materials cus-tomarilyemployedhave acetyl values of about 53.0 to 55.5%, calculated ascombined acetic acid, and are soluble in acetone. It has been commonpractice to dye such textile materials with dispersed cellulose acetatedyestuffs to produce coloredmaterialsb However, the fastness to washingof these colored materials has not been as good as desired- Thus, forcertain purposes it is necessary to have colored materials which showafastmess to washing sufiicient to meet the requirements of the #3 washfastness test of the American Association .of Textile Chemists andColorists. This test involves Washing a specimen of the dyed material at150 C. for 45 minutes under certain standard conditions and'observingthe change, if any, in the color of the dyed material and the stainingcaused by running of the dye from said material. It has generally notbeen possible, by the use of dispersed cellulose acetate dyestufi, toobtain dyed cellulose acetate textile materials, particularly suchtextile materials dyed in full shades, capable of passing theaforementioned #3 test. *In fact this #3 test is so rigorous that,generally speaking, only a Very limited group of dyed materials, e.g.vat-dyed cotton or'regenerated cellulose, will pass the test. 3

It is an important object of this invention to produce a dyed textilematerial having extremely good wash fastness, e.g. wash fastnesssuflioient to pass the aforesaid #3 A.A.T. C.C. wash fastness test.

A further object of this invention is the production of novel textilematerials having improved properties, such as improved wash fastness;fastness to perspiration; resistance to crocking and Wet bleeding;fading and sublimation; resistance to glazing; higher safe ironingtemperatures; ability to form pleats which are permanent to laundering;increased resistance to wrinkling during washing; and decreasedshrinkage when the fabric is pressed in the presence of moist steam.

Another object of this invention is to produce a novel textile materialof cellulose triacetate or other cellulose acetate of very high acetylvalue.

Still another object of this invention is the development of an improvedprocess for dyeing cellulose acetate of very high acetyl value rapidlyand in full shades.

Other objects of this invention will be apparent from the followingdetailed description and claims.

In accordance with one embodiment of this invention, a textile materialof cellulose acetate of very high acetyl value, i.e. of 59% to 62.5%acetyl content, calculated as ice resulting dyed textile material isthen subjected to heat temperature of the textile fabric, an improvementin its resistance to glazing, and also an improvement in its resistanceto mussing and wrinkling during laundering. Also, the treatment, whichdoes not materially alter the hand or strength of the fabric, imparts tothe fabric an ability to be permanently pleated and causes amarked'decrease in the degree to-which the fabric will shrink when it ispressed with moist steam.

As stated, the dyeing of the cellulose acetate of very high acetyl valueis carried out in a heated aqueous bath of adispersed cellulose acetatedyestuffof the high temperature,slowidyeing type. This classof dyestuffsis well known to the art and is represented by such compounds as2-nitro-4-sulfonanilido diphenylamine; V p 4' ethoxy 2-nitrodiphenylamine fi hydroxy propylsulfonamide i4-nitr-o-2-methoxyphenyl azo '4-bis (betahydroxyethyl)amino-'2'-acetylaminobenzene;

itro-2-methylsulfonephenyl azo 4'-(N-beta-hydroxyethyl-N-difluoroethyl)aminobenzene;

'4 nitro 2 -chlorophenyl azo 4 bis(beta hydroxyethyl)amino-2-methylbenzene;

1 -hydroxyethylamino 4 hydroxyethylamino- 5 hydroxy-8hydroxyanthraquinone; V p

4-nitrophenyl azo 4'-di-fi-hydroxyethyIaminO-Z acetamh nobenzene; v I

a mixture of 1*,4-di(hydroxy-ethylamino)-5,8-dihydroxy anthraquinone and1-amino-4-anilido anthraquinone, 1,5 dihydroxy 8 nitro 4 (meta alphahydroxyethyl) anilido anthraquinone;

1,8 dihydroxy-4-(para-beta-hydroxyethyl) anilido-S-nitro anthraquinone;

l-amino-4-anilido anthraquinone; and

2,4-dinitro-6-chlorophenyl azo 4'-b is (hydroxyethyl)amino-2Gacetylarnino-5 -metl1oxy benzene.

These dyestuffs, as sold, are in the form of mixtures of a dispersingagent, such as sodium lignosulfonate or the sodium salt offormaldehydenaphthalene sulfonic acid condensation product, with theactual dye material, and usually contain about 30 to 45% of the actualdye material. Commercial dyestuffs of this type include those sold underthe names Setacyl Blue G; Eastman Blue GL 'Interchemical Blue 'RLF-40(Pr. 227); Celliton Blue AF (PL 227); Red'Y; Celliton Blue Green BA (Pr.229); Eastone Red 2B-GLF; Amacel Red 213; Amacel Yellow CW; Eastone RedGLP; Arnacel Rubine IX (Pr. 239); Scarlet lll (Pr. 244); EnterchemicalBlue (ELF- 40; Interchemical Blue-Green BALF-40 (PL 229) and AmaoelViolet Blue F81. All of these dyestufis are characterized by the factthat when applied to the ordinary cellulose acetate'textile materials,of 53 to 55.5% acetyl value, under certain standard conditions at 0.,they will dye said textile materials in full shades, but when the samedyestulfs are applied to the same textile materials under said standardconditions at a lower temperature, i.e. 60 C., the textile materialswill be dyed only to a small extent, e.g. in shades whose depths areonly about 65% or less of the depths of the full shades. The standardconditions mentioned above involve a treatment of 1 part by weight ofthe fabric in 50 parts by weight of an aqueous dyebath comprising 0.5gram per liter of soap, e.g. sodium oleate, and 1% (based on the weightof the fabric) of dyestuff.

tuna i It has been found that cellulose triacetate and other celluloseacetates of very high acetyl value are generally resistant to dyeingwith the previously described dispersed cellulose acetate dyestuffs ofthe high temperature slow dyeing type. For example, when Celliton BlueAF, which is of the high temperature type, is employed as the dyestufffor both ordinary cellulose acetate and cellulose triacetate at 80 C.,under identical conditions, the depth of shade on the triacetate aftertwo hours of dyeing is only 20 or 25% of the depth of the shade obtainedon the ordinary cellulose acetate after one hour of dyeing. Someimprovements can be obtained by increasing the temperature of thedyebath up to its boiling point. Thus, when the temperature of thedyebath raisedto 95 C.

' the depth of shade on the cellulose triacetate is increased to 30%, ascompared with the 20 or 25 obtained at 80 C.

In accordance with this invention, it has been found that the rate ofdyeing of cellulose triacetate and other cellulose acetates of very highacetyl value may be greatly increased by carrying out the dyeing withthe aqueous dyebath in the presence of certain assistants which aresubstantive to said cellulose acetates. By the use of these assistantsthe cellulose acetates of very high acetyl value may be dyed in fullshades and within commercially acceptable periods of time usingdispersed cellulose acetate dyestuffs of the high temperature slowdyeing type. These full shades may be attained at temperatures wellbelow the boiling point of the dyebath at atmospheric pressure.

The assistants employed in accordance with this invention are, asstated, substantive to the cellulose acetate of very high acetyl value.Thus, when fibers of said cellulose acetate of very high acetyl valueare placed in an aqueous bath containing the assistant uniformlydispersed therein, e.g. in an aqueous bath containing 0.05 to 0.2% ofthe assistant based on the weight of the bath and having a temperatureof 65 to 90 C., the assistant is absorbed on the fiber in a quantitywhich is larger, usually several .times larger, than the quantity whichwould be absorbed by the fiber by mere imbibition of the aqueous bath,so that the concentration of said assistant in the aqueous bath isreduced. The assistant should also be a good solvent for the dyestuffand should preferably have alimited solubility in water. For example,one of the preferred assistants of this invention, tripropyl phosphate,has a water solubility of less than 0.9% at 25 C. and about 0.5% attemperatures of 50 to 95 C., while the other assistants are generallyeven less soluble.

Outstanding results have been obtained by using as the dyeing assistantssuch materials as the terpene alcohols, e.g. pine oil, and their ethers,e.g. the terpene glycol ether known as Terposol #8, such esters asrtripropyl phosphate, tributyl phosphate, triamyl phosphate, trihexylphosphate, dioctyl acid phosphate, dimethyl-phthalate, diethyl phthalateand dipropyl phthalate, diallyl phthalate, triallyl citrate, methylsalicylate, methyl benzoate, and the N,N-dihydroxyethyl amides of higherfatty acids, such as capric or lauric acids, which N,N-dihydroxyethylamides may be prepared by reacting diethanolamine with the higher fattyacid at an elevated temperature'while splitting out water. Othermaterials which have been found to be effective as assistants includesuch aromatic compounds as cumene, biphenyl, naphthalene,tetrahydronaphthalene, trichlorobenzene, cyclohexyl phenol, o-phenyl phenol,salicylic acid, benzoic acid, the monophenyl ether of ethylene glycol,the monodichlorophenyl ether of ethylene glycol, and the monop-chlorophenyl ether of ethylene glycol, the monophenyl ether ofdiethylene glycol, acetophenone, dibutyl phthalate, and 2-methyl-5-ethylpyridine, and such aliphatic and cycloaliphatic materials asdecanol, triootyl phosphates, e.g. tri-n-octyl phosphate, dipropyl acidphosphate, dibutyl acid phosphate, diamyl acid phosphate, didecyl acidphosphate, dilauryl acid phosphate, dibutyl ethanolamine, diisobu-tylcarbitol, Maypon K (a condensatign product of a protein split offproduct and a fatty acid), Alkamine W-30 (a fatty amine condensate), andCR1. 40229-62125, (an ester produced by condensing laun'c acid and 8 to10 moles of ethylene oxide), and the aryl amine known as Kar-In.However, the latter materials are not considered to be as usefulgenerally as the previously mentioned preferred assistants, i.e. terpenealcohols and others, tripropyl, triamyl, trihexyl and tributylphosphates, dirnethyl, diethyl, diallyl and dipropyl phthalates, dioctylacid phosphate, triallyl citrate, methyl salicylate, methyl benzoaxte,and the fatty acid-diethanol amine condensation products, since in manycases the materials are toxic; or too highly volatile; or do notsufficiently solubilize certain of the dispersed acetate dyestuffs ofthe high temperature type; or have some tendency to produce spottingunless added dispersing agents are present; or do not increase thedyeing rate to, the same extent as said preferred assistants; or are attimes deleterious to the mechanical properties and dimensions of thefabric.

Mixtures of dyeing assistants may be employed if desired. For example,excellent results have been obtained by the use of a mixture of tributylphosphate and the condensation product of diethanolamine and capricacid, e.g. N,N-dihydroxyethyl capramide, said mixtures containing forexample, at least 20%, e.g. 50%, of each of these assistants. Othermixtures of dyeing assistants which have given excellent results are,for example, a mixture of equal parts of pineoil and the aforementionedcondensation product of diethanolamine and capric acid; a mixture of 40%by weight of tributyl phosphate, 40% by weight of pine oil and 20% byweight of the afore mentioned condensation product of diethanolamine andcapric acid; a mixture of 40% by weight of tripropyl phosphate, 40% byweight of tributyl phosphate and 20% by weight of the aforementionedcondensation product of diethanolarnine and capric acid.

Generally speaking, the dyebath should contain a dispersing agent inorder to insure that the dye is properly dispersed. As pointed outpreviously, the commercially available dispersed cellulose acetatedyestuffs are preparations containing such dispersing agents in intimatemixture with the actual dye material. It is the usual practice in thedyeing of ordinary acetone-soluble cellulose acetate to incorporate intothe dyebath additional amounts of dispersing agent beyond those amountspresent in the commercial dyestuff. However, we have found that in thedyeing of cellulose triacetate and other cellulose acetates of very highacetyl value in the presence of assistants, the presence of an excessiveamount of the dispersing agent generally causes a decrease in the rateof dyeing. Accordingly, it is usually desirable to maintain the amountof dispersing agent in the dyebath at a minimum value, commensurate withthe particular dyestuff and dyeing conditions. On the other hand,certain dispersing agents having a substantivity for the fiber may beemployed to aid the action of the dyeing assistant. Thus, thecondensation product of diethanolamine and capric acid, which possessessome dispersing properties and detergent action, rnay be used to aid inthe dispersing of tributyl phosphate or pine oil, for example.

When the amount of dispersing agent is too small the material may beunevenly dyed. For example, the dyed fabric may exhibit round, moreheavily dyed spots when the assistant employed is not self-dispersiblein 'water and insufficient dispersing agent is present. Accordingly,when such an assistant is used sufiicient dispersing agent should bepresent to insure even dyeing under the particular dyeing conditionsemployed. Thus, in many cases a higher ratio of dispersing agent toassistant, eg. up to about 1:5, should be used when a more concentrateddyebath is employed, as in a jig-dyeing, than when a relative ly dilutedyebath is employed, as in winch dyeing. If

desired, fabric showing the spots. mentioned above may be treated toremove the spots by scouring the fabric thoroughly at a hightempenature, e.g. 95 C., in the presence of a strong emulsifying agent,such as the nonionic reaction product of oastor oil and ethylene oxidesold under the name .mulphor ELA-7l9; the scoured spot-free fabric maythen be redyed.

The dyeing assistant may be added directly to the aqueous dyebathtogether with the dyestuff, or it may be applied to the surfaces of thetextile material before said textile material is brought into contactwith the dyebath.

' In the latter case, the process of this: invention is advantageouslycarried out by padding a dispersion of the dyeing assistant, e.g. anaqueous emulsion containing the assistant and la dispersing agent, [ontothe surfaces of a fabric comprising fibers of the cellulose acetate ofvery high acetyl value, and then introducing the resulting wet fabricinto the dyehath.

In the practice of this invention, rthe aqueous dyebath is maintained atan elevated temperature, best results being obtained at temperatures ofat least albouult 65 C. Temperatures up to the boiling point of thedyebath may be employed, and, in fact, the dyebath may be maintainedunder superatmospheric pressure in order that it may be heated totemperatures well above the normal boiling point of said dyebath, butthis has not been found to be necessary tfinom a practical standpoint.

The amount of assistant, the pH of the dyebath, the proportion ofdyestufif in the dyebath, and the liquor ratio; i.e. the ratio of theweight of the ldyebath to the Weight of the fabric, may be variedwidely. 'I hus, excellent results have been obtained when the amount ofassistant in the dyebath has been varied from about 5 to 20% (based onthe weight of the fabric) and when the pH of the dyebath has varied fromabout 6 to 9. It is preferred, of course, to employ dyebaths containingminimum amounts of the assistant. With respect to the amount of thedyestuif, this is of the same order as that generally employed indyebaths containing dispersed cellulose acetate dyestuffs, eg. about 0.1to 4.0% (based on the weight of the fabric). For best results the liquorratio should not be too high, eg. it should not be above about 80,preferably about 50 or less, e.g-. about 50 to 30 when the dyeing iscarried out in a winch, since at higher liquor ratios the dyebath isgenerally too dilute. When methods other than winch dyeing are used forbringing the dyebath into Contact with the material to be dyed, theliquor ratio is appreciably lower, e.g. about 10 in the case of packagedyeing and about 5 in the case of jig dyeing.

When the assistant is applied to the textile material before the textilematerial is brought into contact with the dyebath, the total amount ofdyeing assistant used may be reduced substantially, particularly in thecase of those dyeing assistant-s, such as, for example, rtripropylphosphate, tributyl phosphate, dimethyl phthalate and dibutyl pbthalate,which are not removed readily from the surfaces of the textile materialby the dyebath. Thus, an emulsion having a concentration of about 1 to5% of dyeing assistant may be applied to the fabric in an amount "aboutequal to the weight of the fabric (eg. about 75 to 100% of emulsionbasedon the weight of the fabric) at a temperature of, say, 20 to 60 C.,before the fabric is introduced into a dyebath containing no addeddyeing assistant. Though the total amount of dyeing assistant used isthen only about 1 to 5%, based on the weight of the fabric, the resultsare equal to or better than those obtained using larger amounts, e.g. 5to 20% of assistant, in the dyebath. In fact, when this method is usedinstead of the method in which the assistant is added :directly to thedyebath, the rate of dyeing is generally higher so that the dyeingperiod is shortened considerably. With those assistants which :are moreeasily removed from the surface of the fabric by the action of thedye'bath,

such as the condensation product of diethanolamine land ,capric acid, itis preferable to use dispersions containing a higher concentration ofthe assistant, eg. about 5 to 10%, when the dispersions are applied tothe fabric before the latter is brought into contact with the dyebath.

After the textile material made of cellulose triacetate or othercellulose acetate of very high acetyl value has been dyed, it is rinsed,in the manner well known in the dyeing art, to remove dyebath componentsother than the dyestuff and is then subjected to the heat treatment inaccordance with this invention. The heat treatment has the effect ofimproving the wash fastness, perspiration fastness, and other propertiesof the textile material, e.g. safe ironing temperature, ability to takepermanent pleats, glazing resistance, and moist steam pressingshrinkage.

The temperature at which the heat treatment is carried out and theperiod of treatment depend to some extent on the heat treating medium.Thus, when hot air is employedas a heating medium, an improvement in theproperties of the textile material may be obtained by the use oftemperatures of about C., though optimum results are obtained atconsiderably higher temperatures, e.g. at temperatures of about 250 C.Thus, heat treatment of a dyed staple fiber, yarn or woven fabric ofcellulose triacetatc in hot air at a temperature of 190 C. for 20minutes effects a considerable improvement in the wash fastness of thematerial and the safe ironing temperature of the fabric, but only arelatively minor improvement in the resistance to glazing and resistanceto shrinkage on moist steam pressing, while heat treatment of the samefabric in hot air at a temperature of 250 C. for several seconds resultsin a very marked improvement in all of these properties. Furthermore, aswill be evident from the results described in the preceding sentence,the desired improvement in the properties of the textile material may beobtained much more quickly when the higher temperatures are employed.For best results, the heat treatment should not be carried out at suchtemperatures and for such long periods of time as to materially impairthe color, tensile strength and elongation at break, or other mechanicalproperties, of the textile material.

The heat treatment is a dynamic process and involves the heating up ofthe textile material to the elevated temperature. Actually, it isthought that the textile material need be at this elevated temperaturefor only a very heat sources having very high temperatures in order toshorten the time of treatment is not altogether practical since theouter surface of the fiber or fabric may then reach a temperaturesufficiently high to cause damage before the interior of the fiber orfabric has reached the proper temperature. In addition it is verydifiicult to measure the exact temperatures actually attained by thefabric during heat treatment.

It will be therefore apparent that for commercial heat treatment of anyparticular fabric and with any particular apparatus it is best to makesome simple trials in order to determine the best conditions for heattreatment. Such trials are carried out easily and quickly by exposingsamples of the fabric to heat in the apparatus to be used, employingvarious conditions of time and temperature and by observing thecharacteristics of the treated samples, such as safe ironing point andextent of degradation, if any.

The textile material may be heat-treated in the relaxed condition orwhile it is held undertension. The heattreatment maybe carried out whilethe dimensions of the textile material are maintained substantiallyconstant, as by the use of a frame or tenter. Heat-treatment in therelaxed condition results in some shrinkage of the textile material.This shrinkage is very small in the case of cellulose acetates havingacetyl values above 61%. Thus, when a yarn of cellulose acetate havingan acetyl value of 611.3% is heated in a relaxed condition to atemperature of 250 C. for 30 seconds and then cooled,

of 40 continuous filaments of cellulose triacetate.

the yarn shrinks only about 4%. The shrinkage is normally less whenwoven fabric, rather than yarn, is heattreated.

The heat treatment in the relaxed condition, With accompanyingshrinkage, is often desirable when it is necessary to avoid removal ofthe crimp in the fibers making up the textile material and to avoidflattening of the fabric.

The optimum times for heat treatment will depend to some extent on theWeight and construction of the fabric, since, fer example, a longerperiod of time be required to bring the fabric to the desired elevatedtemperature in the case of a heavier, or more tightly Woven fabric thanin the case of a lighter or more loosely waves fabric. Thus a relativelylight woven fabric having a weight of about 4 ounces per square yard,described more fully below, is advantageously heated hot air at atemperature of about 230 C. for at least about 5 seconds, but not aboveabout 1 minute in order to avoid damaging the fabric, preferably forslightly less than 1 minute. For the same fabric at temperatures of 250C. and 270 C., the corresponding times are at least about 5 seconds andat least about 2 seconds, respectively, and not above about 30 secondsand not above about .15 seconds, respectively. When a relatively heavyfabric, having a weight of about 6 /2 to 7 ounces per square yard andmade up of staple fibers, described more fully below, is employed, thecorresponding maximum times are double those given above, is. about 2minutes, 1 minute and 30 seconds at temperatures of 230, 250 and 270 C.,respectively, while the minimum times are about double or somewhat morethan double the minimum times given for the relatively light fabric.When maximum improvement in the resistance to glazing and to shrinkageon moist steam pressing is desired, the heat treatment should becontinued for as long as it is possible to do so without materiallydamaging the fabric. Thus, by suitable heat treatment of a fabric of acellulose acetate having an acetyl value of 61.3 the shrinkage onrepeated moist steam pressing can be reduced. to less than 4% and thetendency for the fabric to glaze on pressing and ironing can bepractically eliminated.

The relatively light fabric referred to above is composed of yarns of150 denier, each yarn being made up The fabric is of 2 over 1 twillconstruction and has 120 ends and 72 picks per inch. 7

The relatively heavy fabric referred to above is com posed of staple 3denier 2 inch long fibers, spun to 20s 2-ply yarn (cotton count) with atwist of 15 -Z in the singles and 14 S in the ply, and woven 44 ends and42 picks per inch in a tropical suiting construction.

When saturated steam is used as the heating medium the heat treatmentmay be effected at lower temperatures. Thus a significant improvement inthe properties of the fabric may be obtained by treating the fabric withsaturated steam at a pressure of 20 pounds per square inch gauge for aperiod of five minutes, although a treating period of 30 minutes givesbest results at this pressure. Steam at higher pressures, e.g. 30 to 50pounds per square inch gauge may also be employed. When treating withsteam it is desirable to prevent any droplets of condensate from comingin contact with the'material being treated since such droplets sometimescause spotting of the dyed material.

If desired, other heat treating media may be employed, e.g. superheatedsteam, hot oil or molten metal, or the textile material may be heated bysubjecting it to a high frequency electric field or to infraredradiation, or the textile material may be heated by contact with hotrolls or hot platens. The heat treatment may be carried out atatmospheric, superatmospheric or even subatmospheric pressure.

Heat treatment tends to cause the fabric to stififen slightly. Thisstiffness may be eliminated by subjecting 8. the fabric to mechanicalworking, e.g. to the operations known as button-breaking or coldcalendering or to wet processing, e'. g. washing or decatizing. Thetendency to stiffening may also be overcome by the application of a veryfinely divided solid material to the textile material before heattreatment; for example, a dispersion of silica, suchas those anionicdispersions of one micron particles of silica known as Ludox or SytonW-20 or DS, may be applied to the fabric for this purpose. The leaststilfening of the fabric has been observed when the heat treat ment iseffected by the use of steam under pressure, e.g. in an autoclave. 7

As stated, the safe ironing temperature of the textile material isimproved significantly by the heat treatment of this invention. Forexample, the safe ironing temperatu're of fiabrics composed of fibersofcellulose triacetate or of cellulose acetate of acetyl value 59.5%,calculated as combined acetic acid, is not above about 190 C. e.g. about180 C. On heat treating such fabrics in accordance with this inventionthe safe ironing temperature is raised by more than about 20 C., to avalue of above about 220 C. or 230 C., usually above about 240 C.

The effect of the heat treatment is most pronounced in the caseof thosecellulose acetates ihaving the highest acetyl values. Thus, for example,cellulose acetates having acetyl values of about 61% or 62% or higher,calculated as combined acetic acid, show greater improvements, onheat-treatment, in resistance to glazing, resistance to moist steampressing shrinkage and in safe-ironing temperature as compared withcellulose acetate of acetyl value of 59.5%, calculated as combinedacetic acid. In

contrast, when a fabric of ordinary cellulose acetate, e.g.

of 54.5% acetyl value, is subjected to the heat-treatment of thisinvention the fabric is damaged severely. For optimum properties forfabrics sold on a commercial scale, the acetyl value should be at least60% and preferably at least 61%.

In accordance with one aspect of this invention, the

heat treatment may be applied to dyed textile materials which the majorportion of the dye has been absorbed -only on the surface of the fibers.Thus, when certain dyeing assistants,'e.g. polybasic acid esters such astributyl phosphate, dimethyl phthalate and diethyl phthal'ate,

are employed, it is observed that even at tenr-penatures as low as 65 C.there is an initial strike of the dye onto the fiber'to producea-peripherally dyed, or surface dyed material during the early stages ofdyeing. 'I he fiber is truly dyed as shown by the fact that examinationof fiber 'cross se'ctions reveals that the dye is within the fiber, andthe fact thatthe dye is not removed by rinsing. When this material issubjected to a heat treatment in accordance with this invention, thedyed material becomes highly fast to washing and does not crock due inpart to further diffusion of dyestuif into the fiber cross section.

, Heat-treatment in accordance with this invention has the additionaleffect of removing a large part of the dye- 1ng assistant from thetextile material. Since the dyeing assistants are substantive to thecellulose acetate of very high acetyl value, an appreciable proportionof these assistants remains in the textile material after the dyeingoperation, even after the textile material is rinsed or scoured. Forexample, two portions of a fabric of cellulose acetate having an acetylvalue of 61.3%, which portrons had been dyed, one in the presence oftributyl phosp li'ate as the assistant and the other in the presence oftripropyl phosphate, were found, after scouring at F., to have P0contents, resulting from the presence of the above phosphates, of 1.64%and 1.44%, respectively. After the portions of fabric had been heatedfor 31 seconds by subjecting them to infra-red radiation so that theirsurfaces attained a temperature of about 245255 C., their P0 contentswere reduced to 0.12% and 0.08% respectively, due to vaporization of thephosphates. Similar results are obtained with other assistants volatileat the temperatures of heat treatment, e.g. pine oil. HOW- 9 ever, thehigh temperature slow dyeing cellulose acetat dyestuffs employed in thisinvention do not volatilize or decompose to any appreciable extentduring the heat treatment and remain substantially entirely in thetextile material.

In some cases it is advantageous to scour the textile material after theheat treatment. Such scouring has been found to reduce any tendency thematerial may have to stain the Water used for the first homeorlaundry-washing thereof, presumably by the removal of a very smallamount of loosely adherent dyestuff. This scouring treatment may becarried out, for example, at a temperature of 120 to 150 F. using anaqueous scouring bath containing 0.5 to 2 grams per liter of a non-ionicor anionic detergent such as Emulphor ELA-719 or Duponol RA7 Any of theusual finishing agents may be applied to textile materials produced inaccordance with this invention. For example, there may be applied to thetextile material a silicone finish composed of a polysilox-anecontaining methyl or other hydrocanbon groups, and preferably alsohydrogen atoms, directly attached to the silicon atoms. Other finishingagents which may be applied include Waxy polyethylene; waxy sulfonatedfatty materials; waxy cationic long chain amine compounds; finelydivided silica; finely divided titanium dioxide; and resinous orresinforming condensation products such as the reaction prodnets ofmelamine, steararnide and formaldehyde. Other resinous or resin-formingcondensation products which may be applied include the reaction productsof formal- -dehyde with urea or thiourea or substituted and cyclic ureassuch as ethylene urea, or melamine, alkylation products of such reactionproducts, e. g. dimethoxymethyl urea,

trimethoxymethyl melamine or N,N-dimethoxymethyl ethylene urea. Theamount of finishing Iagent applied is relatively small, e.g. about Mrto2%, and the finishing agent is most conveniently used by applying to thetextile material an aqueous dispersion of said finishing agent,following which the textile material is dried :and, when it is necessaryto cure said finishing agent as in the case of silicones or resinouscondensation products, then baked at an elevated temperature. Suitablefinishing agents are sold dyed material before but preferably after theheat-treating operation. However, certain finishing agents, such as thesilicones, e.g. Decetex 104, maybe applied to the textile material andcured even before the dyeing with-out appreciably affecting the rate ofdyeing. Those finishing agents which act as surface lubricants, i.e. thesilicones, the waxy polyethylenes and other waxy softeners, and thecondensation products of melamine, formaldhyde and steanamide, increasegreatly the resistance of the dyed textile material to abrasion, whichabrasion sometimes causes fragments of fibers to break OE and thus givesthe appearance of crocking. Such finishing agents also improve the tearstrength of the material. Combinations of finishing agents may beemployed, e.g. combinations of silicones or waxy polyethylenes withureaformaldehyde or melamine-formaldehyde condensation products, orcombinations of dispersed finely divided silica and silicones, together,if desired with ureaor melamine-formaldehyde condensation products.

Cellulose acetate of very high acetyl value colored with certaindispersed cellulose acetate dyestuffs shows a tendency to fade onexposure to acid fumes, such as combustion gases and, in some casesonexposure to ozone. To reduce this tendency it is often desirable toapply a suitable inhibitor to the textile material. The inhibitor may beapplied, for example, by including it is the dyebath, by padding on asolution or dispersion of the inhibitor before or after dyeing, or byapplying the inhibitor after the heat-treatment. 'It is generallydesirable to apply the inhibitor before the heat-treatment. Examples ofsuitable inhibitors are those conventionally employed for ordinaryacetone-soluble cellulose acetate, such as diphenylimidazolidine, N,Ndiphenylethylenediamine, N,

N-dibenzylethylenediamine and methyl or other alkyl substiution productsthereof, diphenylbenzamidine, diphenyl- :acet-amidine,benzylethylaniline, sodium formate or Meleine (melamine which has beenpartly solubilized in water by reaction With a small amount offormaldehyde). For prevention of fading by ozone, antioxidants, e.g.tertiary butyl hydroquinone, alkylated phenols such as Ionel andInhibitor 162, and many of the aforementioned nitrogenous inhibitors,may be employed. The amount of inhibitor is generally small, e.g. 0.5 to3% based on the weight of the textile material. I

It is found that, even Without the use of an inhibitor, dyed textilematerial of cellulose acetate of very high acetyl value which has beenheat-treated in accordance with this invention shows a much smallertendency to fade on exposure to ozone than the same dyed fabric beforeheat-treatment.

' As stated, heat-treated fabrics of this invention are capable of beingpermanently pleated. Thus, in one example, a heat-treated fabric ofcellulose acetate having an acetyl value of 61.3% is accordion-pleatedon a steam press using 500 pounds head pressure while steaming for 10seconds with steam having a pressure of 50 pounds per square inch gauge;the pleats are retained on washing. Permanent pleats may also beobtained by pleating the fabric before or during the heat-treatment; forexample, a fabric which has not'been heat-treated may be pleated betweenmetal nollls having a temperature of 350 F. and then furtherheat-treated, e.g. with steam at a pressure of 20 pounds per square inchgauge in an autoclave.

If desired, the cellulose acetate textile material of very high acetylvalue may also be embossed with any suitable pattern before, during orafter heat treatment. For example, a woven fabric of cellulose acetateof very high acetyl value which has not been heat-treated may be given asurface pattern which is fast to washing by the applica- Zion of a metalembossing roller having a temperature of While the process of thisinvention has been described particularly in connection with textilematerials composed entirely of fibers of cellulose acetate of very highacetyl value, it is also applicable to other textile materialscomprising such fibers, e.g. to materials made up of blends of suchfibers and other fibrous materials, such as wool, cotton, rayon, glassfibers and asbestos. Such blends may be dyed under such conditions thatall types of fibers in the blend are colored at the same time or theymay be dyed in stages so as to color the different types of fiberssuccessively. The blends of fibers may be cross-dyed or union-dyed. Theprocess of this invention is applicable to textile materials made up ofstaple fibers of cellulose acetate of very high acetyl value as Well asthose made up of continuous filaments of said cellulose acetate.

Although the heat treatment of this invention is of greatest value andyields optimum results when used on cellulose acetate textile materialsof very high acetyl value dyed with cellulose acetate dyestuffs of thehigh temperature slow dyeing type, it may also be applied to such highacetyl value cellulose acetate textile materials dyed with otherdyestuffs, e.g. with low temperature or medium temperature types ofdispersed cellulose acetate dyestuffs such as 2-nitro 4-su1fonamidodiphenylamine, p-nitrophenyl aZo diethyl aniline or l-amino 4-hydroxyanthraquinone. In such cases the safe ironing temperature, resistance toglazing, resistance to shrinkage on moist steam pressing and ability totake permanent pleats are improved, as is the Wash fastness of thematerial, but there is not a suflicient aromas 1 1 improvement in thelatter property to enable the material to pass the #3 A.A.T.C.C. washfastness test. Furthermore, the materials dyed with dyes of the hightemperature slow dyeing type generally posses superior resistance to gasfading, light fading and sublimation.

After the heat treatment of this invention the cellulose acetate textilematerials of high acetyl value are much more resistant to dyeing thanthe same materials before the heat treatment. However, the rate at whichthe heat-treated materials take up the dye may be markedly increased bythe use of the dyeing assistants previously described and by the use ofhigher dyebath temperatures, e.g. temperatures of 95 to 100 C. andhigher.

The following examples are given to illustrate the invention further.

Example I (a) A woven fabric composed of fibers of cellulose acetatehaving an acetyl value of 62.0 to 62.5%, calculated as combined aceticacid, said fibers having been produced by spinning a solution of saidcellulose acetate in a mixture of 90% of methylene chloride and 10% ofethanol into an evaporative atmosphere, is dyed in accordance with thisinvention. The fabric used'is of 2 over 1 twill construction weighingabout 4 ounces per square yard and having 120 ends per inch and 72 picksper inch, each yarn in both weft and warp having a denier of 150' andbeing composed of 40 continuous filaments. The dyeing operation iscarried out for one hour in an aqueous dyebath maintained at atemperature of 85 C. and containing 2% (based on the weight of thefabric) of the dyestuff Eastman Blue GL (containing about 40% active dyematerial consisting of 1,8-dihydroxy-4-(parabetahydroxyethyl)anilido-S-nitro anthraquinone), 10% (based on the weight of the fabric)of tri-n-propyl phosphate, and 1% (based on the Weight of the fabric) ofIgepon T Gel, a dispersing agent which comprises as its activeingredient 16% of the sodium salt of oleyl taurate. The liquor ratio,i.e. the ratio of the weight of the dye'bath to the weight of thefabric, is 50. After the dyeing operation the wet fabric is rinsed for15 minutes at 35 C. in a bath containing 2 grams per liter of soap, anddried.

Four other portions of the same fabric are dyed. The conditions ofdyeing, which are diiferent in each case, are identical with the dyeingconditions given in paragraph (a) above with the following exceptions:

(b) There is substituted for the tripropyl phosphate an equal weight ofpine oil.

There is substituted for the of tripropyl phosphate, 10% (based on theWeight of the fabric) of Alrosol C, a condensation product produced byheating two moles of diethanolamine with one mole of capric acid whilesplitting out the Water of reaction, said condensation productcomprising N,N-dihyd-roxyethyl capramide. This condensation product is aliquid soluble in Water and in organic solvents; its water solutions areclear, thin and slightly alkaline, do not gel on dilution with Water andtolerate electrolytes.

' (d) The dyebath contains no added assistant or Igepon T, but merelythe Eastman Blue GLF and water.

(e) The dyebath contains no added assistant, but merely the Eastman BlueGLF, Water and 1% (based on the weight of the fabric) of the Igep'on T.

The following table compares the results obtained in the above dyein-gs:

Type of dyehath Color of fabric (a) Tripropyl phosphate, Igepon T" Deepblue shade.

(b) Pine oil, Igepon T and water Shade almost as deep as (a). (e)Alrosol O and water Shagdo somewhat lighter than (d) Water (e) Igepon Tand water Very pale shade, much lighter than (c).

Paler than (d).

12 Example [I The procedure of Example 1(a), (b), (c), (d) and (e) isrepeated except that the dyestuff Celliton Blue AF (containing about 40%of active dye material) is substituted for the Eastman Blue GLF. Theresults are tabulated below:

Type of dyebath Color of fabric (a) Tripropyl phosphate, Igepon T Deepblue shade.

and Watt (a) A Woven fabric composed of fibers of cellulose acetatehaving an acetyl value of 62.0 to 62.5%, calculated as combined aceticacid, said fibers having been produced by spinning a solution of saidcellulose acetate in an organic solvent therefor into an evaporativeatmosphere, is dyed for one hour in an aqueous dyebath maintained at atemperature of C. and containing 1% (based on the weight of the fabric)of the dyestuff Eastone Red GLF, comprising4-nitro-2-methylsulfonephenyl azo 4' (Nbeta-hydroxyethyl-N-difluoroethyl) aminobenzene, 10% (based on theweight of the fabric) of pine oil, and 1% (based on the Weight of thefabric) of a dispersing agent comprising equal proportions, by weight,of the dispersing agents known as Emulphor ELA-719 (a non-ionic productof the reaction of castor oil and ethylene oxide) and Quadronate (amahogany soap, i.e. a sodium petroleum sulfonate, of low molecularWeight). The liquor ratio is 50 and the fabric is washed after thedyeing operation in a manner similar to Example I, and dried.

The other portions of the same fabric are dyed. The dyeing procedures,which are different for each of said portions, are identical with thoseset out in the preceding paragraph, with the following exceptions:

(b) There is substituted for the 10% of pine oil 10% (based .on theweight of the fabric) of Alrosol C and the dispersing agent is omitted.

(c) The pine oil and dispersing agent are omitted.

The results are tabulated below:

than (b).

Example IV The dyed fabrics of the preceding examples (I, II and III)are heat treated in an oven in circulating hot air having a temperatuneof 230 C. for 60 seconds while said fabrics are held in frames tomaintain their dimensions substantially constant throughout the heattreatment. The heat treated fabrics are subjected to the A.A.T.C.C. #3Wash fastness test and are found to retain their color, Withoutappreciable change of color or staining, even after 3 repetitions ofsaid test. The heat treatment raises the safe ironing temperature of thedyed fabric by 60 C., i.e. from 180 C. to 240 C., improves the glazingresistance of the fabric, and reduces the degree of wrinkling whichoccurs during laundering. The heat treated fabric shrinks 9% in areaafter 12 pressings in moist steam, as compared with a 15% shrinkage forfabric which has not been heat-treated. The heat-treated fabric may bepleated in a steam press using a damp cloth and high mechanical presspressure, and the resulting pleats are permanent to repeated Washing atF. The hand and strength of the fabric is substantially the same beforeand after heat treatment.

The safe ironing temperature, referred to above, is determined by theuse of a standard hand iron having a weight of five pounds and an areaof its sole plate of 22 /2 square inches. The test is conducted byheating the iron until a selected 2-inch square area of the sole plateadjacent the tip of the iron has the desired temperature. A 2-inchsquare of the fabric to be tested is placed on an ironing surfacecomprising a flat board covered with one inch of sponge rubber, overwhich are 4 layers of cotton flannel, and the iron is then placed on thefabric so that the aforesaid selected area of the sole plate coincideswith the fabric. The placing of the iron is carried out by hand withoutany lateral'motion of the iron on the fabric and without any applicationof hand pressure to the iron on the fabric. After the iron has rested onthe fabric for exactly 10 seconds, the iron is lifted straight up offthe fabric. The test is repeated with the iron heated in 10 C.increments for each test until there is evidence of damage to thefabric, e.g. until the fabric sticks to the iron, becomes boardy orchanges-in color. The maximum safe ironing temperature is thattemperature which is 10 C. below the temperature at which the first signof damage to the fabric occurs.

Example V The procedure of Example 1(a) is followed except thattri-n-butyl phosphate in the amount of 5% (based on the weight of thefabric) is used in place of the tripropyl phosphate; the dispersingagent is a mixture of (based on the weight of the fabric) of EmulphorELLA-719 and A1 (based on the weight of the fabric) of Quadronate; thedyestulf is Amacel Rubine IX and is used in the amount of 2% based onthe weight of the fabric; and the dyeing is carried out at 80 C. Thefabric is dyed a full red shade.

Example VI A portion of the woven fabric described in Example I is dyedfor -30 minutes in an aqueous dyebath maintained at a temperature of 65C. and containing 2% (based on the weight of the fabric) of the dyestuftCelliton Blue AF (containing 40% active dye material), (based on theweight of the fabric) of tri-n-butyl phosphate, and 0.5% (based on theweight of the fabric) of Quadronate and 0.5% (based on the weight of thefabric) of Emulphor ELA-7l9. The tributyl phosphate, which is a liquid,is first mixed with the Emulphor ELA-7l9 and Quadronate and theresulting paste is then mixed with the water of the dyebath. The liquorratio is 50. After thedyeing operation the wet surface dyed fabric isrinsed for minutes at 35 C. in a bath containing 1 gram per liter ofIgepon T Gel. The fabric is dyed a deep blue shade. When this materialis subjected to a heat treatment in accordance with this invention, itbecomes highly fast to washing and does not crock.

Example VII A portion of the woven fabric described in Example I ispadded at a temperature of 50 C. with a bath comprising an emulsioncontaining 5% by weight of trianbutyl phosphate, /2% of EmulphorELA-719, /2%

fof Quadronate and the remainder water, all of said proportions beingbased on the total weight of the emulsion. After the fabric has been incontact with the padding bath for 30 seconds, the fabric, carrying 100%of its weight of said emulsion, is introduced into, and maintained forA2 hour at 85 C. in, a dyebath containing 2% (based on the weight of thefabric) of Celliton Blue AF, the liquor ratio being 50. The fabric isdyed a full blue shade.

Example VIII Example I is repeated except that the fabric is com- 14posed of fibers of cellulose acetate having an acetyl value of 59.5%,calculated as acetic acid. Substantially the same results are obtainedas in Example I.

The dyed fabric is subjected to the heat treatment described in ExampleIV for a period of 30 seconds. Sub- 'stantially the same results as inExample IV with respect to wash fastness are obtained. The safe ironingtemperature is raised and the pleating characteristics, resistance towrinkling and mussing during laundering, and resistance to pressingshrinkage in moist steam are im proved, but not nearly to as great anextent as in the case of Example IV.

Example IX kilograms of woven fabric of cellulose acetate of 61.3%acetyl value are placed on a jig, scoured, and dyed on the jig at aliquor ratio of 4:1 with an aqueous mixture comprising 3000 grams ofCelliton Blue AF, 390 grams of Eastone Red GLF, 420' grams of AmacelYellow CW, 950 grams of diphenylimidazolidine, 50 grams of Igepon T Gel,100 grams of tetrasodium pyrophosphate and 2500 grams of a mixture of400 parts by weight of tripropyl phosphate, 400 parts by weight of thepine oil sold under the name Yarmor 350 (a mixture of hydrocarbons andalcohols, distilling in the range of 190220 C., with about 50%distilling at about 200 'C., at atmospheric pressure) and 100 parts byweight of Emulphor ELA719. The dyeing is started at 85 C. and after 2hours the temperature of the dyebath is raised to 95 C. Total dyeingtime is 6 hours, during which time the fabric is passed from one roll ofthe jig through the dyebath and rolled onto the other roll of the jigand then passed through the dyebath to the first roll, this operationbeing repeated several times during the dyeing period, in theconventional manner. Thereafter the fabric is scoured'and washed on thejig. The fabric, dyed a heavy navy blue shade, is heat treated in aradiant heating. apparatus for 30 seconds, during which time the fabricattains a temperature of 230 C., and then subjected to the A.A.T.C.C. #3wash fastness test, during which there is no appreciable change inshade.

Example X A tfabric composed of a blend of 50% of staple fibers ofcellulose acetate of 62.5 acetyl value and 50% of viscose rayon staplefibers is dyed, at a liquor ratio of 50:1, with an aqueous bathcomprising 1% Eastman Blue GLF 2% Eastone Red GLF, 0.75% InterchemicalAcetate Yellow HDLF-40, 0.21% Resofix Blue GL-N, 0.45% Cuprofix Yellow(31. and 2.5% Resoiix Rubine BLN, the latter three being direct dyes forcellulose, all proportions being based on the Weight of the fabric. Thedyebath also contains 10%, based on the Weight of the fabric, of AlrosolC. 10%, based on the weight of the fabric, of sodium chloride is addedin portions during the dyeing. The temperature of dyeing is C. Thefabric is dyed in a uniform medium brown shade. It is rinsed, then heatset by exposing it to radiant heat for 30 seconds, during which time thefabric attains a temperature of 220 C., and thereafter padded with anaqueous mixture in such a manner as to deposit on the fabric 0.5% byweight of Decetex 104, 0.5 by weight of Decetex, 108 (both Decetexcompositions being silicone finishing agents), 10% by Weight of a lowcondensation product of 1.3 moles of formaldehyde and 1 mole of urea, 1%by weight of Catalyst G-S" (an acidic mixture of formaldehyde and anamine hydrochloride curing catalyst for the urea-formaldehyde product)and 2% by weight of Cuprofix 47" (a fixative agent for direct dyes oncellulose), all proportions being based on the weight of the fabric.After drying the fabric is heated at 155 C. for 8 minutes to cure thefinish and then scoured.

Example XI parts by Weight of a fabric of cellulose acetate of 62.5%acetyl value are immersed and agitated for one 15 hour in a bath havinga temperature of 85 C. and comprising 4000 parts by weight of water, 2parts by weight of the dyestuif Celliton Blue Green BA, containing about40% by weight of active dye material and the balance disp'ersin'g agent,and parts by weight of tr'i-ri-bu'tyl phosphate. The fabric is thenrinsed in water and dried.

The resulting dyed fabric is analyzed to determine its content oftri-n-but yl phosphate and dye, and the dyebath is analyzed to determinethe concentration of tri-n-butyl phosphate therein.

For comparison, the dyeing is repeated under identical conditions exceptthat in one instance the phosphate is entirely omitted from the dyebathand, in the other cases, and equal amount of tri-n-ethyl ortri-n-p'rop'yl phosphate is employed in place of the tributy-lphosphate. 1

1 Based on weight of the dyed fabric. 1 Based on the weight of thedyebath.

Exa mp le XII A fabric of cellulose acetate of 62.5% acetyl value ispadded with an emulsion prepared by vigorously blending 99% of Water and1% of tri-n-butyl phosphate. In the padding operation the fabric isfirst dipped into the emulsion for 2 minutes at 25 C. and then passedbetween pressure pad rollers. The padded fabric, carrying an amount ofemulsion equal to about 90% its own weight, is then dyed at 85 C. for 1hour with an aqueous dispersion of 2%, based on the weight of the fabricbefore padding, of Celliton Blue Green BA, at a liquor ratio of 40. Thefabric is then rinsed and dried. The resulting dyed fabric is analyzedto determine its content of tri-n-butyl phosphate and dye.

For comparison, the procedure described above is repeated, using nophosphate in the padding bath, or using tri-n-ethyl phosphate ortri-n-propyl phosphate in place of the tri-n-butyl phosphate, all otherconditions being 1 Based on the weight of the dyed fabric.

Example XIII 100 parts by weight of a textile fabric of celluloseacetate of 61.3% acetyl value are immersed and agitated in a dyebathcontaining 5000 parts by weight of water, 3 parts by weight of CellitonFast Blue AF, 12.5 parts by weight of diethyl phthalate and 2.5 parts byweight of Tween 85 (a polyoxyethylene sorbitan trioleate). The dyeing isstarted with the dyebath at a temperature of 60 C., which is raised to90 C. as the dyeing progresses. The fabric is dyed in a full, very levelblue shade.

Example XIV Other examples of mixtures of dyeing assistants anddispersing agents suitable for use with the aforementioned 16 "celluloseacetate dyes of the high temperature slow dyeing type are:

(n) 4 parts by weightof tributyl phosphate 4 parts by weight of Yarmor350 1 part by Weight of Emulphor ELA-7l9 3 parts by weight of tributylphosphate 3 parts by weight of tripropyl phosphate 1 part by Weight ofEmulphor ELA-7l9 3 parts by weight of tributyl phosphate 2 parts byweight of Yarmor 350 2 parts by weight of .Alrosol C p 1 part by weightof Emulphor ELA719 4 parts by weight of diethyl phthalate 4 parts byweight of tripropyl phosphate 1 part by weight of Tween 4 parts byweight of phenyl ether of ethylene glycol 4 parts by weight of vphenylether of diethylene glycol 0.5 part by weight of.Span 20 0.5 part byweight 'of Tween 20 It is to be understood that the foregoing detaileddescription isgiven merely by way of illustration and that manyyariations may be made therein without departing from the spirit ofourinvention.

Having described our invention, what we desire to secure by LettersPatent is:

1. Process for the treatment of textile material, which comprises dyeinga textile material comprising fibers of cellulose acetate having anactyl value of at least 59%, calculated as combined acetic acid, with adispersed cellulose acetate dye of the high temperature slow dyeingtype, and heat-treating the resulting dyed textile material forimproving the wash fastness of the dyed material.

I 2. Process as set (Slit in claim 1 in which the textile material is inthe form of a fabric and the fabric is allowed to shrink during saidheat treatment.

3. Process as set out in claim 1 in which said cellulose acetate has anacetyl value of at least 61%. g

Process as set out in claim 1 in which the heat treatmerit is carriedout in air until the safe ironing temperatune of the material is raisedto at least 230 C.

5. Process as set out in claim 1 in which the heat treatmerit isconducted in substantially saturated steam under pressure; p M I, I

6 A textile material produced by the process of claim 1.

7 A textile material produced by the process of claim 3. v V i 8.Process as set forth in claim 1 in which the heat treatment is carriedout to raise the .safe ironing temperature of said material to at least230 0. whereby the wash fastne ss of the dyed material is increased.

9. Process as set forth in claim 1 in which the heat treatment iscarried out at a temperature ranging from about C. to 270 C. and isdiscontinued before any substantial damage to the textile materialoccurs.

10. The process which comprises heat treating a textile materialcomprising fibers of cellulose acetate having an acetyl value of atleast 59%, calculated as combined acetic acid, said fibers includingwithin their cross-sections particles of dispersed cellulose acetate dyeof the high temperature sl'ow dyeing type.

11. Process as set forth in claim 10 wherein said textile materialincluding said dye particles is scoured prior to said heat treatment.

12. Process as set forth in claim 10 wherein said heat treatmentiscarried out at a temperature ranging from about 190 C. to 270 C. andis discontinued before any substantial damage to the textile materialoccurs.

13. Process for the treatment of textile material, which comprisesdyeing a textile material comprising fibers of cellulose acetate havingan acetyl value of at least 59%, calculated as combined acetic acid,with a dispersed cellulose acetate dye of the high temperature slowdyeing type, in an essentially aqueous bath at a temperature betweenabout 65 C. and the boil, removing said textile material from said bath,scouring said dyed textile material, and heat-treating the scoured dyedtextile material for improving the wash fastness of the dyed material.

14. Process as set forth in claim '13 wherein said heat treatment iscarried out at a temperature ranging from about 190 C. to 270 C. and isdiscontinued before any substantial damage to the textile materialoccurs.

References Cited in the file of this patent UNITED STATES PATENTSDreyfus May 11, 1937 Platt Aug. 20, 1940 Sprague Ian. 15, 1957 FinlaysonDec. 2, '1958 Salvin et al. May 2, 1961

1. PROCESS FOR THE TREATMENT OF TEXTILE MATERIAL, WHICH COMPRISES DYEINGA TEXTILE MATERIAL COMPRISING FIBERS OF CELLULOSE ACETATE HAVING ANACTYL VALUE OF AT LEAST 59%, CALCULATED AS COMBINED ACETIC ACID, WITH ADISPERSED CELLULOSE ACETATE DYE OF THE "HIGH TEMPERATURE SLOW DYEINGTYPE," AND HEAT-TREATING THE RESULTING DYED TEXTILE MATERIAL FORIMPROVING THE WASH FASTNESS OF THE DYED MATERIAL.